1. Field of the Invention
The present invention pertains to the field of digital computer memories and particularly to dynamic memories in which there is a continuous circulation of data.
2. Description of the Prior Art
In copending application Ser. No. 578,685, entitled "Digital Memory with Data Manipulation Capabilities," filed on May 19, 1975, in the names of Murray Edelberg and Lloyd R. Schissler, and assigned to the assignee of the present invention, and hereby incorporated by reference into the present application, a computer memory is disclosed which is formed of serial circulating storage loops and distributed processing logic, preferably for application with CCD (charge-coupled devices) or magnetic bubble memory technologies. In addition to the basic information storage function, the memory performs high speed, off-line sorting, associative searching, updating and retrieval. As disclosed in Ser. No. 578,685, the memory stores one data record per loop (single record storage loop) and is capable of dynamically altering its loop size to accommodate varying record length requirements.
There are, however, economical and technological reasons why alternatives to single record storage loops are desirable. For example, while on-chip logic for the processing element is reasonable for CCD memories, it does not, at present, appear feasible for magnetic bubble memories. With off-chip logic, long storage loops (longer than the single record storge loops for storing multiple records) are required in order to maintain reasonable pin counts. Furthermore, longer storage loops result in lower ratios of processing element chip area to storage loop area and thus lower memory system cost per bit of storage.
The conversion of the intelligent memory described in Ser. No. 578,685 to accommodate long storage loops into which multiple data records are packed is, in some respects, straight-forward. It can be appreciated, however, that the sort mode of operation for a packed storage loop memory system presents a serious obstacle which must be overcome in order to extend the intelligent memory system of Ser. No. 578,685 to packed circulating storage loops (packed with multiple records).